At present, the 3D (three-dimensional) display technology has attracted a lot of attentions, and its most fundamental principle is: different pictures are received by left and right eyes of a person, respectively, and then are subjected to superimposing, renascence of image information, etc., in a brain, thereby forming a stereoscopic image.
The current 3D display technology is mainly classified into a naked-eye 3D display and a glasses 3D display, and a common naked-eye 3D display technology is to add a layer of liquid crystal grating to a display screen. As shown in FIG. 1, a common liquid crystal grating generally comprises an upper polarizer, a lower polarizer, an upper substrate, a lower substrate and a liquid crystal layer between the two substrates, and strip-like electrodes and a plane electrode are provided on the upper substrate and the lower substrate, respectively. Its specific operation principle is as follows: when the liquid crystal grating is electrified, liquid crystal molecules corresponding to the strip-like electrodes are deflected, and other liquid crystal molecules remain the same. In this case, when a light enters from the lower polarizer, a polarized light parallel to an absorption axis of the lower polarizer enters the liquid crystal layer, will change its vibration direction upon passing through the liquid crystal molecules that remain the same without deflection, and its vibration direction is just parallel to an absorption axis of the upper polarizer when it reaches the upper polarizer, so that the light pass through; while passing through the liquid crystal molecules that are deflected, the polarized light will not change the vibration direction, and its vibration direction is perpendicular to the absorption axis of the upper polarizer when it reaches the upper polarizer, so that the light is blocked. As such, a parallax barrier perpendicular to an extending direction of strip-like electrodes is formed, thereby achieving the three-dimensional grating display mode. In this mode, when an image to he seen by a left eye is displayed on a display screen, a right eye will be sheltered from it by opaque stripes, and likewise, when an image to be seen by the right eye is displayed on the display screen, the left eye will be sheltered from it by opaque stripes. By means of separating left and right pictures, a three-dimensional display effect is realized.
If touch and three-dimensional display functions need to be realized simultaneously, two layers of touch electrodes insulated from each other will generally be added to the upper substrate of the liquid crystal grating. In this case, the liquid crystal grating having a touch function has at least four layers of electrode, and a large number of electrode layers will reduce the transmittance of the whole liquid crystal grating. And, as both the upper and lower substrates are provided with electrodes, a conductive adhesive needs to be used for conduction of a voltage signal, and alignment marks also need to be provided on the two substrate, respectively, so as to be precisely cell-assembled for use, which increases the fabrication cost as well.